Nicole (Nicola Cowper) is a prostitute in a high class brothel run by madam Pepperdine (Ingrid Pitt) and tonight she has gone upstairs for rest and preparation, but outside a group of masked figures are advancing on the building. They manage to break into her bedroom and kidnap her, despite the efforts of the staff to stop them she is quickly spirited away and one kidnapper's mask is removed to reveal he is some kind of red-eyed monster. The next day, reformed gangster Roy Bain (Larry Lamb) is called on by his former boss, Motherskille (Steven Berkoff) and reluctantly agrees to hunt Nicole down and save her. First, he has to visit Pepperdine, but the trail will lead to something stranger than a simple abduction...
Not to be confused with the Kate Beckinsale as a PVC-clad vampire movie of the 2000s, this Underworld was brought to you from a script by a certain Clive Barker, working with James Caplin from his own story. Nowadays it looks as eighties as it's possible to get without actually being a member of Duran Duran while playing on a ZX Spectrum and watching (and enjoying) an episode of The Kids from Fame, but in effect it's about as entertaining as The Miners' Strike. Signs of the trademark Barker pretentions are already there, but with none of the flair, as this is basically a nineteen-thirties mad doctor movie dressed up for its period.
For some reason, Ingrid Pitt has blue hair in this, and Larry Lamb has bright red streaks in his hair which really don't suit a man of his age, but let's not worry about that. The rest of the plot, such as it is, sees Bain indulging in a spot of investigating, and becoming suspicious that Motherskille has ulterior motives for wanting to track down Nicole. Pepperdine and her workers are strangely reluctant to divulge much information about where Nicole could have gone, but a phial of a white solution he finds puts ideas in his head and pushes him in the right direction.
The phial contains a new drug developed by Dr Savary (Denholm Elliott), who is keen to see Bain leave almost the minute he turns up at his door. What he's been up to will explain the kidnapping, but first Bain and a prostitute who has invited herself round to stay the night at his flat must contend with the man-monster we saw at the start of the film, a mutant called Red Dog (Gary Olsen) who has escaped the confines of his underground dwelling. Bain manages to fend of the attack by shooting him, and promptly follows the maniac back to his lair, which also handily happens to be where his mutant friends hang out.
Of course the drug that Savary manufactures has turned these former heroin addicts into slumming British actors with latex on their faces, but strangely it has no discernable effect on Nicole other than preserving her youth. Just what Savary intended the concoction to do is unclear, but you'll have lost interest by the time he shows up anyway. Underworld moves at a snail's pace, and its attempts to fashion a classy horror fall flat - I mean neon tubes as decoration, really. In fact, Clive Barker was so upset with the way this film developed that he vowed never to let anyone other than himself direct his work ever again. EVER. Well, OK, that's not true, but he must have felt that way for a bit. Music by Freur, i.e. the guys that went on to have hits as Underworld in the nineties, although aside from nicking the title you'd never guess it from this.